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United States Patent |
6,054,790
|
Kjeer
,   et al.
|
April 25, 2000
|
V-block arrangement for a dynamo-electric machine
Abstract
A V-block with a preselected shape defining a preselected included angle
between a pair of V-block side portions is connected to a laminated spider
of a rotor at preselected location between spaced apart adjacent poles of
the rotor by disposing an elongated connecting piece in a slot
longitudinally disposed in the spider and connecting the elongated
connecting piece to the V-block by a fastener. Applying a preselected
torque to the fastener establishes a predetermined force between the
V-block and the conductive windings disposed about adjacent poles. The
V-block arrangement is particularly suited for use in a dynamo-electric
machine.
Inventors:
|
Kjeer; Pete (Mankato, MN);
Morrison; Darrell R. (Mankato, MN)
|
Assignee:
|
Emerson Electric Co. (St. Louis, MO)
|
Appl. No.:
|
274541 |
Filed:
|
March 23, 1999 |
Current U.S. Class: |
310/214; 310/261 |
Intern'l Class: |
H02K 003/48 |
Field of Search: |
310/214,194,261,269
|
References Cited
U.S. Patent Documents
894015 | Jul., 1908 | Kishi et al. | 310/269.
|
2899573 | Aug., 1959 | Wesolowski | 310/60.
|
3739212 | Jun., 1973 | Koelbel et al. | 310/194.
|
4268773 | May., 1981 | Beck et al. | 310/269.
|
4409502 | Oct., 1983 | McCabria | 310/61.
|
5036238 | Jul., 1991 | Tajima | 310/214.
|
5086246 | Feb., 1992 | Dymond et al. | 310/269.
|
Other References
Morrison, et al., Rotor V-Block Assembly, U.S. Patent Application No.
09/158,368, filed Sep. 22, 1998.
|
Primary Examiner: Ramirez; Nestor
Assistant Examiner: Waks; Joseph
Claims
We claim:
1. A V-block arrangement for a dynamoelectric machine having a rotor, said
rotor having a spider, a plurality of spaced apart poles disposed in a
circular array around the spider, a plurality of conductive windings
encircling the poles, and an axis of rotor rotation; comprising:
a plurality of V-blocks having a predetermined fixed shape and being
disposed between a pair of said spaced apart poles;
a slot disposed in said spider between said pair of spaced apart poles,
said slot extending in a direction substantially parallel to the axis of
rotor rotation;
an elongated connecting piece disposed in said slot;
a plurality of fasteners extending radially relative to said axis of
rotation and adjustably connecting said elongated connecting piece to said
plurality of V-blocks.
2. The V-block arrangement, as set forth in claim 1, wherein said spider
includes apertures disposed radially therein and opening into the slot,
said fasteners being disposed in the radial apertures.
3. The V-block arrangement, as set forth in claim 2, wherein said fasteners
are slidably and loosely disposed in the radial apertures.
4. The V-block arrangement, as set forth in claim 2, wherein at least one
of said V-blocks includes a pair of side portions, an apex end portion at
a connection of the pair of side portions, and a strut end portion spaced
from the apex end portion and rigidly connected to and between the pair of
side portions, said strut maintaining the pair of side portions at a
preselected angle relative to each other.
5. The V-block arrangement, as set forth in claim 4, including a pair of
spaced apart blocks of a non-conductive insulating material, wherein said
V-block is disposed between the pair of spaced apart blocks such that the
side portions of the V-block engage said pair of blocks and urge said pair
of blocks toward a respective one of said pair of spaced apart poles.
6. The V-block arrangement, as set forth in claim 5, wherein said pair of
spaced apart blocks engage a respective pole winding encircling the
respective poles.
7. The V-block arrangement, as set forth in claim 5, wherein said spider
includes a plurality of laminations being stacked to define an axial
length of said spider.
8. The V-block arrangement, as set forth in claim 4, wherein said fastener
corresponding to the at least one V-block forcibly urges said V-block
having said predetermined fixed shape toward the axis of rotor rotation
and applying a predetermined force to the windings encircling the
respective pair of adjacent poles.
9. The V-block arrangement, as set forth in claim 8, wherein having a
preselected axial length, said slot extending the length of the spider,
and said elongated said slot has a second axial length, said elongated
connecting piece has a third axial length, and wherein the second axial
length is longer than the third axial length.
10. The V-block arrangement, as set forth in claim 9, wherein said
elongated connecting piece and said slot are circular in a cross section
taken perpendicular to said axis of rotor rotation and said elongated
circular connecting piece is slidably disposed in the circular shaped
slot.
11. The V-block arrangement, as set forth in claim 10, including:
a threaded aperture disposed in the elongated connecting piece;
a clearance aperture disposed in the V-block and opening at the strut and
apex portion end portions the V-block, said fastener being screwthreadably
connected in the threaded aperture in said elongated connecting piece,
slidably disposed in the clearance aperture in the strut portion of the
V-block, and engageable with the strut portion of the V-block.
12. The V-block arrangement, as set forth in claim 9, wherein said
elongated connecting piece and said slot are dovetail-shaped in a
cross-section taken perpendicular to said axis of rotor rotation, and said
elongated dovetail-shaped connecting piece is slidably disposed in the
dovetail-shaped slot.
13. The V-block arrangement, as set forth in claim 12, including:
a clearance aperture disposed in the apex portion of the V-block;
a clearance aperture disposed in the elongated connecting piece, wherein
said fastener is a bolt which is slidably loosely disposed in the
clearance aperture in each of said elongated connecting piece and said
apex portion; and
a nut screwthreadably connected to the bolt and engageable with the apex
portion of the V-block.
14. The V-block arrangement, as set forth in claim 13, including a
clearance aperture disposed in the strut portion, said nut being
accessible through the clearance aperture in the strut portion.
Description
TECHNICAL FIELD
This invention generally relates to a rotor of a dynamo-electric machine
and more particularly to a V-block arrangement for maintaining windings in
position about poles of the rotor of the dynamo-electric machine and
method of assembly thereof.
BACKGROUND ART
A V-block with relatively adjustable sides forcibly maintains the windings
of adjacent poles of a rotor of a dynamo-electric machine, such as an
electric motor, generator and the like, in position on the poles during
rotation of the rotor. A plurality of adjustable V-blocks spaced axially
along the length of the rotor and engaged with the windings is required to
adequately maintain the windings in position on the poles during rotation
of the rotor.
It has been found difficult to accurately adjust the included angle between
the sides of each adjustable V-block properly in order to maintain an
equal force against the windings. It has also been found that adjustment
of the included angle between the sides of a V-block is time consuming and
difficult to achieve in its own right. In some rotors more than 100
V-blocks are required making the total adjustment time excessive.
Through practice, it has been found, that welding the rotor laminations
together, drilling and tapping the welded rotor laminations, and threading
a bolt into the tapped hole to retain the V-block is also unsatisfactory.
Such a process is time consuming and costly and results in localized high
stresses in the welded laminated rotor at the tapped hole. Such stresses
may cause failure of the laminated rotor during operation thereof.
The subject invention is directed at overcoming one or more of the problems
set forth above.
DISCLOSURE OF THE INVENTION
In one aspect of the present invention, a V-block arrangement for a rotor
of a dynamo-electric is provided. The rotor has a spider, a plurality of
spaced apart poles disposed in a circular array around the spider, a
plurality of conductive windings encircling the poles, and an axis of
rotor rotation. The V-block arrangement has a V-block with a predetermined
fixed shape. The V-block is disposed between a pair of said spaced apart
poles. A slot which extends in a direction substantially parallel to the
axis of rotation of the rotor is disposed in the spider at a location
between the pair of spaced apart poles. An elongated connecting piece is
disposed in the slot. A fastener extending radially relative to the axis
of rotation connects the elongated connecting piece to the V-block.
The V-block being connected to the elongated connecting piece disposed in a
slot in the spider eliminates individual boring and tapping of the
laminated rotor and the stresses associated with such a construction.
The V-block having a predetermined fixed shape eliminates the need for the
difficult relative adjustment of the included angle of the V-block sides.
The fastener connecting the elongated connecting piece to the V-block
provides for ease of access and the accuracy of adjustment of the radial
position of the V-block relative to the rotor and thereby the resultant
force of the V-block being applied to the windings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagrammatic isometric view of a rotor assembly showing an
embodiment of the V-block arrangement of the present invention;
FIG. 2 is a diagrammatic end view of FIG. 1;
FIG. 3 is a diagrammatic isometric view of one embodiment of the V-block
arrangement of the present invention;
FIG. 4 is a diagrammatic isometric view of another embodiment of the
V-block arrangement of the present invention;
FIG. 5 is a diagrammatic cross sectional view taken along lines 5--5 of the
V-block arrangement of FIG. 3; and
FIG. 6 is a diagrammatic cross-sectional view taken along lines 6--6 of the
V-block arrangement of FIG. 4.
BEST MODE FOR CARRYING OUT THE INVENTION
With reference to the drawings and in particular FIGS. 1-4, a rotor 10 for
a dynamo-electric machine (not shown) is shown in detail. The particular
rotor 10 depicted is for use in an electric generator. However, other
applications including electric motors and the like are considered within
the field of use of this invention.
The rotor 10 has a shaft 12 defining an axis of rotor rotation 14, a spider
16 with a plurality of spaced apart poles 18 disposed in a circular array
equally around the spider 16. A plurality of conductive windings 20
encircle the poles 18. The spider 16 consists of a plurality of lamination
plates 22 stacked together defining the axial length of the spider 16. The
poles 18 are laminated and connected to the laminated plates 22 of the
spider 16.
A V-block arrangement 23 having a plurality of identical V-blocks 24 with a
predetermined fixed shape is disposed between each pair of the spaced
apart poles 18. The V-blocks 24 are spaced a predetermined distance apart
along the length of the spider 16. The spacing and quantity is determined
as a function of the number required to adequately support the conductive
windings 20. Preferably, the V-blocks are equally spaced. The V-blocks 24
have a pair of side portions 26,28, an apex end portion 30 at a connection
of the pair of side portions 26,28 and a strut end portion 32 spaced from
the apex end portion 30. The strut end portion 32 is rigidly connected to
and between the pair of side portions 26,28 and maintains the pair of side
portions 26,28 at a preselected included angle "a" relative to each other
and provides no relative angular side adjustment. Preferably, the V-blocks
24 are formed in one piece from a material having adequate strength,
manufacturability, and low cost, such as aluminum.
A slot 34 is disposed in the spider 16 between each pair of spaced apart
poles 18. The slot 34 may be formed by stamping, machining or any other
suitable process. The slots 34 extend in a direction substantially
parallel to the axis of rotor rotation 14 and the full length of the
spider 16.
An elongated connecting piece 36 is disposed in each slot 34. Each
elongated connecting piece 36 is preferably shorter in length than the
length of the slot 34 in order to accommodate generous tolerances and to
insure that the elongated connecting piece 36 does not extend past
opposite ends of the spider 16. Each elongated connecting piece 34 is
positioned into the slot 34 from an end 38,40 of the spider 16.
As shown in the embodiment of FIGS. 1-3 and 5, each elongated connecting
piece 36 and each slot 34 is circular in cross-section and preferably
round. The each circular elongated connecting piece 36 is slidably
disposed in a circular shaped slot 34 to facilitate assembly and
disassembly.
As shown in the embodiment of FIGS. 4 and 6, the elongated connecting piece
36 and the slot 34 are dovetail shaped in cross-section. The elongated
dovetail shaped connecting piece 36 is slidably disposed in a receiving
dovetail shaped slot 34 to facilitate assembly. With respect to this
invention, a dovetail includes other non-round shapes capable of retaining
a member from radial movement, for example, a fir tree shape, a "T" shape,
and the like.
As best seen in FIGS. 1 and 3, the spider 16 has a plurality of spaced
apart radial apertures 42 disposed radially therein relative to the axis
of rotor rotation 14. The radial apertures 42 are substantially equally
spaced in a direction along the length of the spider 16 and lie radially
between pairs of spaced apart poles 18. The radial apertures 42 preferably
bisect the angular space between poles 18 and open into the slots 34. It
is noted that the radial apertures 42 are defined between stacks of
lamination plates 22 so as to not to produce stress risers in the spider
16. The number of radial apertures 42 is a function of the number of
V-blocks 24 selected above. The size of each radial aperture 42 is
sufficient to loosely receive a fastener 44 hereinafter discussed.
As best seen in FIGS. 3 and 4, fasteners 44, extending radially relative to
the axis of rotor rotation 14, adjustably connects the V-blocks 24 to the
elongated connecting pieces 36. The fasteners 44 forcibly urge the
V-blocks 24 toward the axis of rotor rotation 14 and apply a predetermined
force to the conductive windings 20 encircling adjacent poles 18. In the
embodiment of FIG. 3, the elongated connecting pieces 36 are retained
sandwiched between opposite ends (FIG. 1) of the spider 38,40 by a fan
blade assembly 41 connected to the spider 16 at the opposite ends 38,40.
Referring to FIGS. 3 and 5, the fasteners 44 are movably and loosely
disposed in the radial apertures 42. A plurality of threaded apertures 46
are disposed in the elongated connecting piece 36 at predetermined spaced
apart locations along the elongated connecting piece 36 corresponding to
the V-block 24 spacing discussed above. It is noted that, the fasteners 44
and the sides of the radial apertures 42 may engage each other and thereby
maintain the elongated connecting piece 36 from axial movement in the slot
34 without the aid of the fan blade assembly 41.
As best seen in FIG. 5, a clearance aperture 48 opening at the strut and
apex end portions 30,32 is disposed in the V-block 24. The fastener 44
which is shown as a bolt 50, but not limited thereto, is slidably disposed
in the clearance aperture 48, screwthreadably connected to the threaded
aperture 46 in the elongated connecting piece 36, and engageable at a head
end of the bolt 50 with the strut end portion 32 of the V-block 24.
Referring to FIGS. 4 and 6, a plurality of clearance apertures 54 are
disposed in the elongated connecting piece 36 at predetermined spaced
apart locations along the elongated connecting piece 36 corresponding to
the V-block 24 spacing discussed above.
As best seen in FIG. 6, a clearance aperture 56 is disposed in the apex end
portion 30 of the V-block 24. The fastener 44, shown as a machine screw
60, but not limited thereto, is slidably loosely disposed in the clearance
apertures 54,56 disposed in the elongated connecting piece 36 and the apex
portion 30 respectively. It is to be noted that each aperture 54 may be
threaded and the machine screws 60, threaded along the length thereof, are
screw threadably engaged with the threaded apertures 54. This threaded
engagement retains the machine screws 60 in position and assists in
assembly. A nut 58 which is screwthreadably connected to the machine screw
60 is engageable with the apex end portion 30 of the V-block 24. A service
clearance aperture 62 is disposed in the strut end portion 32 to
facilitate access to the nut 58. In particular, the service clearance
aperture provides access for a socket of a wrench (not shown). As seen in
FIGS. 1-6, a pair of spaced apart insulating blocks 64 of a non-conductive
insulating material are disposed between the V-blocks 24 and the
respectively adjacent poles 18. The insulating material which is non
conductive permits a conductive V-block material, such as aluminum, to be
utilized. Each side portion 26,28 of the V-block 24 engages one of the
insulating blocks 64 and urges the insulating blocks 64 towards a
respective one of the spaced apart poles 18. In particular, the pair of
spaced apart blocks 64 are urged to engage a conductive windings 20
encircling the adjacent poles 18 to maintain the windings 20 in position
on the poles 18.
Industrial Applicability
With reference to the drawings and in operation, the V-block arrangement 23
maintains the conductive windings 20 in position on the poles 18 of the
laminated spider 16 and from excessive relative movement during rotation
of the rotor 10 about the axis of rotor rotation 14.
The V-blocks 24 having a predetermined fixed shape insures that the fixed
included angle of the pair of side portions 26,28 of the V-blocks 24 is
maintained constant under all loading conditions. This enables ease of
adjustment of each of the V-blocks 24 and simplicity of assembly and
disassembly. Since the retaining force of the V-blocks 24 applied against
the conductive windings is proportional to the torque applied to the
fasteners 44, adjustment of each of the V-blocks 24 is easily achieved. To
apply a consistent force between each of the V-blocks and the conductive
windings one simply applies adjustment torque to each fastener 44 of an
equal magnitude.
The elongated connecting piece 36 disposed in the slot 34 eliminates the
need for drilling and tapping the spider 16. This eliminates the stress
risers associated with the drilled and tapped spider 16. Since the
elongated connecting piece 36 distributes the load applied by the
fasteners substantially along the length of the elongated connecting piece
34 disposed in the slot 34 localized stresses in the spider are
substantially reduced.
The construction of the V-block arrangement 23, including ease of access to
the threaded fasteners 44, facilitates ease of connection and removal of
the V-blocks 24 not present in other arrangements.
Connection of the V-blocks 24 to the spider 16 is achieved simply by
disposing the elongated connecting piece 36 in the slot 34 connecting the
V-blocks 24 to the elongated connecting piece 36 by the fasteners 44,
installing the insulating blocks 64 between the V-blocks 24 and the
conductive windings 20, and applying a tightening torque to the fasteners
44 of a preselected amount.
In the embodiment shown in FIG. 5, the fasteners 44 are threaded into the
threaded aperture 46 disposed in the elongated connecting piece 36
subsequent to disposition of the elongated connecting piece 36 in the slot
34.
In the embodiment shown in FIG. 6, the fasteners 44 are inserted in the
clearance apertures 54 in the elongated connecting piece 36 prior to
insertion of the elongated connecting piece 36 into the slot 34. As noted
above the, the apertures 54 may be threaded and the fasteners 44 may be
screwthreaded into the apertures 54 prior to insertion of the elongated
connecting piece 36 into the slot 34.
Other aspects, objects and advantages of this invention can be obtained
from a study of the drawings, the disclosure and the appended claims.
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